Ilberd

[Enkidoh]

With an Ascien's help, I can Ilberd shown how to operate Omega. Just like Ultima, Omega will probably lose control

The thing you're forgetting though, is we have no idea how intact Omega really is. After all, look at Ultima Weapon - it was extensively rebuilt by the Garleans to make it functional, so what parts of it were original Allagan tech and what was Nero's magitek additions was unclear. Omega may be completely inoperable and would require extensive reconstruction to bring back online - something I doubt is beyond the limited capabilities of Eorzean engineers (the only ones would could probably do the job would be Cid and the Ironworks, and it's already clear they would vehemently refuse to even touch such a device, and in fact would chastise and criticize anyone who tried to).

That leaves the Skysteel Manufactory in Ishgard and well... the limit of their mechanical expertise is forging dragonkiller cannons - refitting an ancient Allagan superweapon would be completely beyond them (the last time they tried building an airship using magitek technology stolen from the Garleans and.. the ship has never worked - they had to resort to bring in Cid and the Ironworks just to fix the issues with it, without success. And the manacutters weren't even built by the Manufactory - they were constructed by Biggs and Wedge using the Manufactory's facilities).

No, I don't think Omega is going to be anything more than a vague Macguffin mentioned in passing to 'explain' why the Grand Companies are fighting over Carteneau, and won't actually appear in the game itself. But hey, I've been wrong plenty of times before!